Ink jet inks are formulated to provide certain characteristics such as: good penetration into paper; good print quality; small dot size; good jetability; etc.
Unfortunately, it is generally not possible to maximize more than one or two of these characteristics in any particular ink formulation.
Ink compositions usually represent a trade-off in certain characteristics in order to maximize other characteristics.
This trade-off is clearly evident when choosing between different classes of inks, i.e. between aqueously miscible and non-aqueously miscible compositions.
For example, aqueously miscible ink fluids generally provide a high surface tension characteristic for good jetability and small dot formation. Aqueously miscible ink fluids, however, have the drawbacks of: not penetrating well into paper, and having high evaporation rates.
On the other hand, non-aqueously miscible ink fluids provide round dots for good print quality, and also have low evaporation rates. They have characteristic drawbacks of higher viscosity and lower surface tension, which characteristics reduce jetability and increase dot size, respectively.
The present invention suggests a method and composition for blending generally miscible ink fluids, in order to maximize a host of ink characteristics. In this fashion, the invention suggests a way of obtaining the best features of different ink systems or classes. An additional feature of this invention allows for the use of a wider variety of dyes or coloring agents for use in the uniquely blended system, because the dye or coloring agent may be either hydrophilic or hydrophobic; i.e. compatible with either aqueously or non-aqueously miscible components.